XMPP 101

XMPP 101

Remko Tronçon
Peter Saint-Andre

Tuesday, March 3, 2009

Overview
Introduction
XMPP Basics
Example code
Extensions
State of the bulb
Conclusion

2


Introduction


About Us

4


About Us
Peter: Documentation guy and speciﬁcation author

4


About Us
Remko: Developer for Psi client and other projects

4


About Us
Remko: Developer for Psi client and other projects
Co-authors (with Kevin Smith) of XMPP: The
Deﬁnitive Guide (O'Reilly, 2009)

4


About You

5


About You

Why are you here?

5


About You

Why are you here?
What do you want to build?

5


About You

Why are you here?
What do you want to build?
What is your background? (web, client-server, ...)

5


What is XMPP?

6


What is XMPP?
eXtensible Messaging and Presence Protocol

6


What is XMPP?
Jabber

6


What is XMPP?
Jabber
Real time messaging system

6


What is XMPP?
Jabber
Routes small snippets of XML

6


What is XMPP?
Jabber

Alice Sister
alice@wdland.lit sister@rlworld.lit
6


What is XMPP?
Jabber

wdland.lit rlworld.lit
server server

Alice Sister
6


What is XMPP?
Jabber

server server

<message to=’sister@rlworld.lit’>
<body>Hi there!</body>
</message>

Alice Sister
6


What is XMPP?
Jabber

...
server server

<message to=’sister@rlworld.lit’>
<body>Hi there!</body>
</message>

Alice Sister
6


What is XMPP?
Jabber

...
server server

<message to=’sister@rlworld.lit’> <message from=’alice@wland.lit’>
<body>Hi there!</body> <body>Hi there!</body>
</message> </message>

Alice Sister
6


What can you do with XMPP?

7


Instant Messaging

7


Real-time Social Networking

8


Gaming

9


Voice & Video

10


Mobile apps / Geolocation

11



<insert your idea here>

12


XMPP ...

13


XMPP ...
... is an open standard (RFC 3920 + 3921, XSF
Extensions)

13


XMPP ...
Extensions)
... is decentralized (federated)

13


XMPP ...
Extensions)
... has strong security (TLS)

13


XMPP ...
Extensions)
... has lots of open-source projects (but other
licensing allowed)

13


XMPP ...
Extensions)
... has lots of open-source projects (but other
licensing allowed)
... has an active, open community

13


What does XMPP provide?

14


Channel encryption and authentication

14


Presence and contact lists

14


One-to-one and multi-party messaging

14


Alerts and notiﬁcations (PubSub)

14


Service discovery and device capabilities

14


Peer-to-peer media sessions (Jingle)

14


Data forms and remote commands

14


Data forms and remote commands
And more (lots of extensions)

14


History

15


History
Invented by Jeremie Miller as Jabber (1998)

15


History
First server + clients + libraries (1999-2000)

15


History
More open source + commercial codebases
(2000+)

15


History
(2000+)
Core standardization in IETF as XMPP (2002-2004)

15


History
(2000+)
Development of extensions (2002+)

15


History
(2000+)
Serious adoption by Apple, Google, LiveJournal,
Nokia, Cisco, etc. (2005+)

15


History
(2000+)
Serious adoption by Apple, Google, LiveJournal,
Nokia, Cisco, etc. (2005+)
Continuing work on improved security and more
application types
15


Basics


Architecture
Web architecture

17


Architecture
Web architecture

Browser

17


Architecture
Web architecture

wonderland.lit images.realworld.lit
Web Server Web Server

Browser

17


Architecture
E-Mail architecture

18


Architecture
E-Mail architecture

E-Mail client E-Mail client
alice@wonderland.lit sister@realworld.lit

18


Architecture
E-Mail architecture

wonderland.lit rabbithole.lit realworld.lit
server server server

E-Mail client E-Mail client
alice@wonderland.lit sister@realworld.lit

18


Architecture
XMPP Architecture

realworld.lit
wonderland.lit
server
server

XMPP client
XMPP client
sister@realworld.lit
alice@wonderland.lit

19


Architecture

20


Architecture
Client-server

20


Architecture
Client-server
Client developers can focus on user experience

20


Architecture
Client-server
Server developers can focus on relaibility & scalability

20


Architecture
Client-server
Decentralized

20


Architecture
Client-server
Decentralized
Robust (no single point of failure)

20


Architecture
Client-server
Decentralized
Easier to manage

20


Architecture
Client-server
Decentralized
Easier to manage
No multiple hops

20


Architecture
Client-server
Decentralized
Easier to manage
No multiple hops
Harder to spoof

20


Addresses

Jabber ID (JID)

21


Addresses

Jabber ID (JID)
Domain
wonderland.lit

21


Addresses

Jabber ID (JID)
User Domain
alice@ wonderland.lit

21


Addresses

Jabber ID (JID)
User Domain
alice@ wonderland.lit

Bare JID

21


Addresses

Jabber ID (JID)
User Domain Resource
alice@ wonderland.lit /TeaParty

21


Addresses

Jabber ID (JID)
User Domain Resource
alice@ wonderland.lit /TeaParty

Full JID

21


Streaming XML

22


Streaming XML
<stream:stream>

22


Streaming XML
<stream:stream>
<presence/>

22


Streaming XML
<stream:stream>
<presence/>
<iq type=quot;getquot;>
<query xmlns=quot;jabber:iq:rosterquot;/>
</iq>

22


Streaming XML
<stream:stream>
<presence/>
</iq>
<iq type=quot;resultquot;>
<query xmlns=quot;jabber:iq:rosterquot;>
<item jid=quot;alice@wonderland.litquot;/>
<item jid=quot;madhatter@wonderland.litquot;/>
<item jid=quot;whiterabbit@wonderland.litquot;/>
</query>
</iq>

22


Streaming XML
<stream:stream>
<presence/>
</iq>
</query>
</iq>
<message from=quot;queen@wonderland.litquot; to=quot;madhatter@wonderland.litquot;>
<body>Off with his head!</body>
</message>

22


Streaming XML
<stream:stream>
<presence/>
</iq>
</query>
</iq>
</message>
<message from=quot;king@wonderland.litquot; to=quot;party@rooms.wonderland.litquot;>
<body>You are all pardoned.</body>
</message>

22


Streaming XML
<stream:stream>
<presence/>
</iq>
</query>
</iq>
</message>
</message>
<presence type=quot;unavailablequot;/>
22


Streaming XML
<stream:stream>
<presence/>
</iq>
</query>
</iq>
</message>
</message>
<presence type=quot;unavailablequot;/>
</stream:stream> 22


Communication Primitives

Stanzas:

23



Stanzas:
<message/>

23



Stanzas:
<message/>

<presence/>

23



Stanzas:
<message/>

<presence/>

<iq/>

23


Message Stanzas

24


Message Stanzas
<message from=quot;madhatter@wonderland.lit/fooquot;
to=quot;alice@wonderland.litquot;
type=quot;chatquot;>
<body>Who are you?</body>
<subject>Query</subject>
</message>

24


Message Stanzas
</message>

From, To

24


Message Stanzas
</message>

From, To
Types: normal, chat, groupchat, headline, error

24


Message Stanzas
</message>

From, To
Types: normal, chat, groupchat, headline, error
Payloads: Body, Subject

24


Presence Stanzas

25


Presence Stanzas
<presence from=quot;alice@wonderland.lit/pdaquot;>
<show>xa</show>
<status>down the rabbit hole!</status>
</presence>

25


Presence Stanzas
<show>xa</show>
</presence>

Advertise network availability (online/ofﬂine)

25


Presence Stanzas
<show>xa</show>
</presence>

‘Show’ Statuses: Away, Do Not Disturb,
Extended Away, Free for chat

25


Presence Stanzas
<show>xa</show>
</presence>

Status messages

25


Presence Stanzas
<show>xa</show>
</presence>

Status messages
Typically used for contact lists/rosters

25


Presence Stanzas
<show>xa</show>
</presence>

Status messages
Typically used for contact lists/rosters
Presence subscriptions

25


IQ Stanzas

26


IQ Stanzas
</iq>

26


IQ Stanzas
</iq>
</query>
</iq>

26


IQ Stanzas
</iq>
</query>
</iq>
Request/Response

26


IQ Stanzas
</iq>
</query>
</iq>
Request/Response
Workﬂows, execute commands, query information
26


IQ Stanzas
</iq>
</query>
</iq>
Request/Response
Workﬂows, execute commands, query information
Similar to HTTP GET, POST, PUT 26


IQ Stanzas

Sender Receiver

27


IQ Stanzas

IQ-get
Sender Receiver

27


IQ Stanzas

Sender Receiver
IQ-result

27


IQ Stanzas

IQ-set
Sender Receiver

27


IQ Stanzas

28


IQ Stanzas
</iq>

28


IQ Stanzas
</iq>

Types:

28


IQ Stanzas
</iq>

Types:
get: Ask for information (HTTP GET)

28


IQ Stanzas
</iq>

Types:
set: Provide information (HTTP POST/PUT)

28


IQ Stanzas
</iq>

Types:
result: Returns requested information / acknowledge set

28


IQ Stanzas
</iq>

Types:
result: Returns requested information / acknowledge set
error

28


Extensibility

29


Extensibility
Any XML child element can be used as a payload

29


Extensibility
e.g. XHTML bodies, Atom feeds, XML-RPC, ...

29


Extensibility
Namespaces to scope payloads
</iq>

29


Extensibility
</iq>
Extensions typically developed @ XMPP Standards
Foundation's

29


Extensibility
</iq>
Foundation's
Open, developer-friendly standards process

29


Extensibility
</iq>
Foundation's
Open, developer-friendly standards process
Can write your own quot;privatequot; extensions for custom
functionality
29


Asynchronicity

30


Asynchronicity
Web

30


Asynchronicity
Web
Send request to server

30


Asynchronicity
Web
Wait for response

30


Asynchronicity
Web
Wait for response
Short-lived connections

30


Asynchronicity
Web
Wait for response
Jabber

30


Asynchronicity
Web
Wait for response
Jabber
Long lived connection

30


Asynchronicity
Web
Wait for response
Jabber
Events are sent out / come in asynchronously

30


Asynchronicity
Web
Wait for response
Jabber
Events are sent out / come in asynchronously
Different mindsets!

30


Code Example


Echo bot

32


Echo bot
Bots

32


Echo bot
Bots
Unmanned clients

32


Echo bot
Bots
Unmanned clients
Connect to an XMPP server, and wait for commands / send
events

32


Echo bot
Bots
Unmanned clients
events
Echo bot

32


Echo bot
Bots
Unmanned clients
events
Echo bot
Echoes back every message that it receives

32


Writing the Echo Bot

34


Select a language to work in

34


e.g. Python

34


e.g. Python
Select an XMPP library to do the low-level XMPP
work

34


e.g. Python
work
e.g. SleekXMPP

34


e.g. Python
work
e.g. SleekXMPP
Start coding

34


SleekXMPP Python Echo Bot
class EchoBot :
def __init__(self, jid, password) :
self.xmpp = sleekxmpp.ClientXMPP(jid, password)
self.xmpp.add_event_handler(quot;session_startquot;, self.handleXMPPConnected)
self.xmpp.add_event_handler(quot;messagequot;, self.handleIncomingMessage)

def run(self) :
self.xmpp.connect()
self.xmpp.process(threaded=False)

def handleXMPPConnected(self, event):
self.xmpp.sendPresence(pstatus = quot;Send me a messagequot;)

def handleIncomingMessage(self, message) :
self.xmpp.sendMessage(message[quot;jidquot;], message[quot;messagequot;])

def main() :
bot = EchoBot(quot;echobot@wonderland.lit/HelloWorldquot;, quot;mypassquot;)
bot.run()

35


Extensions


Multi-User Chat

37


Multi-User Chat

38


Multi-User Chat
Conversation with multiple users

38


Multi-User Chat
Shared roster (with presence from all participating
users)

38


Multi-User Chat
users)
Crowd control

38


Multi-User Chat
users)
Crowd control
Privacy

38


Multi-User Chat
users)
Crowd control
Privacy
Conﬁgurable

38


Multi-User Chat Conﬁguration

39


PubSub: Polling vs PubSub

Polling PubSub

HTTP client XMPP client
Service

40



Polling PubSub
Poll
Service

40



Polling PubSub

Service
Result

40



Polling PubSub

Service
No Result

40



Polling PubSub
Subscribe
Service

40



Polling PubSub

Service
Publish

40


PubSub

41


PubSub
Protocol to subscribe and publish any kind of
information

41


PubSub
information
Avoids needless polling for new information

41


PubSub
information
Doesn’t scale with the number of users / requests

41


PubSub
information
Extensible: Payload can be any type

41


PubSub
information
Extensible: Payload can be any type
Conﬁgurable

41


PubSub: Subscribing

<iq from=quot;alice@wonderland.lit/rabbitholequot;
id=quot;gh921nx3quot;
to=quot;notify.wonderland.litquot;
type=quot;setquot;>
<pubsub xmlns=quot;http://jabber.org/protocol/pubsubquot;>
<subscribe node=quot;queenly_proclamationsquot;
jid=quot;alice@wonderland.litquot;/>
</pubsub>
</iq>

42


PubSub: Publishing events
<iq from=quot;queen@wonderland.lit/croquetlawnquot;
id=quot;ma019r58quot;
to=quot;notify.wonderland.litquot;
type=quot;setquot;>
<pubsub xmlns=quot;http://jabber.org/protocol/pubsubquot;>
<publish node=quot;queenly_proclamationsquot;>
<item>
<entry xmlns=quot;http://www.w3.org/2005/Atomquot;>
<title>A new thought</title>
<summary>Off with their heads!</summary>
<link rel=quot;alternatequot; type=quot;text/htmlquot;
href=quot;http://wonderland.lit/1865/quot;/>
<id>tag:wonderland.lit,1865:entry-42</id>
<published>1865-12-13T18:30:02Z</published>
<updated>1865-12-13T18:30:02Z</updated>
</entry>
</item>
</publish>
</pubsub>
</iq> 43


PubSub: Receiving events
<message from=quot;notify.wonderland.litquot; to=quot;alice@wonderland.litquot;>
<body>A new thought: off with their heads!</body>
<event xmlns=quot;http://jabber.org/protocol/pubsub#eventquot;>
<items node=quot;queenly_proclamationsquot; id=quot;bl38pahu98hquot;>
<item id=quot;zi2ba967quot;>
<entry xmlns=quot;http://www.w3.org/2005/Atomquot;>
<title>A new thought</title>
<summary>Off with their heads!</summary>
<link rel=quot;alternatequot; type=quot;text/htmlquot; h
ref=quot;http://wonderland.lit/1865/quot;/>
<id>tag:wonderland.lit,1865:entry-42</id>
<published>1865-12-13T18:30:02Z</published>
<updated>1865-12-13T18:30:02Z</updated>
</entry>
</item>
</items>
</event>
</message>
44


Extended Presence

45


Extended Presence
Publish extra information about yourself

45


Extended Presence
What music are you currently listening to?

45


Extended Presence
Where are you right now?

45


Extended Presence
What are you doing?

45


Extended Presence
What are you doing?
Used to be added to regular presence

45


Extended Presence
What are you doing?
Doesn’t scale

45


Extended Presence
What are you doing?
Doesn’t scale
‘Spams’ people with unwanted information

45


Extended Presence
What are you doing?
Doesn’t scale
‘Spams’ people with unwanted information
Implemented on top of PubSub

45


Extended Presence

46


Extended presence

47


Jingle

48


Jingle
Voice, Video, Multimedia, P2P

48


Jingle
XMPP is not optimized to send data streams

48


Jingle
Use XMPP (Jingle) to set up a direct connection
between points

48


Jingle
between points
Negotiate what (Audio/Video) and how (UDP, TCP) you are
going to send it

48


Jingle
between points
going to send it
Use streaming protocols (RTP,...) to stream the data
over the negotiated direct connection

48


Jingle
between points
going to send it
(Renegotiation during data session)

48


Jingle
between points
going to send it
NAT traversal using standard technologies
48


Jingle
between points
going to send it
NAT traversal using standard technologies
TURN, STUN, ICE 48


File Transfer

49


File Transfer
Various ways of transferring ﬁles

49


File Transfer
Tiny pieces of data are sent in one stanza

49


File Transfer
Small pieces of data are sent in a set of consequent <iq/>
stanzas

49


File Transfer
stanzas
Larger pieces of data are sent out of band

49


File Transfer
stanzas
Using SOCKS5

49


File Transfer
stanzas
Using SOCKS5
Using older Jingle-like protocol

49


File Transfer
stanzas
Using SOCKS5
Using older Jingle-like protocol
Being extended to use Jingle

49


BOSH

50


BOSH
Regular XMPP opens one long-lived TCP
connection, and keeps it up

50


BOSH
Not always convenient

50


BOSH
Long connections drain batteries on mobile phones

50


BOSH
Web clients cannot keep state (open connections)

50


BOSH
Bad network connectivity

50


BOSH
Bidirectional streams Over Synchronous HTTP

50


BOSH
XMPP over HTTP

50


BOSH
XMPP over HTTP
Cunning mechanism of not having to poll for new
messages

50


BOSH
XMPP over HTTP
Cunning mechanism of not having to poll for new
messages
Piggyback incoming messages on HTTP response
50


BOSH

POST /webclient HTTP/1.1
Host: bosh.wonderland.lit
Content-Type: text/xml; charset=utf-8
Content-Length: 205

<body rid=quot;90029205quot; sid=quot;3m1ts1htd1squot;
xmlns=quot;http://jabber.org/protocol/httpbindquot;>

<message to=quot;sister@realworld.litquot; xmlns=quot;jabber:clientquot;>
<body>Help, I fell down the rabbit hole!</body>
</message>

</body>

51


Serverless Messaging

52


Sometimes, a server is not available

52


Remote location without internet

52


Conference location with many unknown people you want to
communicate wit

52


communicate wit
Serverless messaging

52


communicate wit
Uses zero-conﬁguration (Apple) to discover entities
on the local network

52


communicate wit
mDNS, DNS-SD

52


communicate wit
mDNS, DNS-SD
Open connection directly to other connection, and
send XMPP over that connection
52


communicate wit
mDNS, DNS-SD
Open connection directly to other connection, and
send XMPP over that connection
iChat’s Rendez-vous/Bonjour 52


State of the bulb


What is the XSF working on?

54


E2E security

54


E2E security
Whiteboarding

54


E2E security
Whiteboarding
File sharing / personal media networks

54


E2E security
Whiteboarding
File sharing / personal media networks
World domination

54


Conclusion


Join the conversation
http://xmpp.org/
mailto:jdev@jabber.org
xmpp:jdev@conference.jabber.org
[mailto:|xmpp:]stpeter@jabber.org
[mailto:|xmpp:]remko@el-tramo.be
Jabber/XMPP booth @ FOSDEM
XMPP Summit on Monday

56


Conclusion

57


Conclusion
The real-time Internet is coming

57


Conclusion
Build competitive advantage using open
technologies

57


Conclusion
technologies
What problems can you solve with XMPP?

57


Conclusion
technologies

57


Conclusion
technologies
Happy Jabbering!

57


Conclusion
technologies
Happy Jabbering!

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57


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Notes de l'éditeur